u-boot.git/drivers/serial, branch main

fix non-existing sysam.it domain

2026-08-28T18:18:11Z

Change "Angelo Dureghello" emails replacing non-existing domain with the currently working one. Signed-off-by: Angelo Dureghello Acked-by: Michal Simek

serial: coreboot: Accept DBG2 subtype 0x12

2026-08-10T20:22:09Z

U-Boot running as a coreboot payload obtains serial console information either from the coreboot table or from the ACPI DBG2 table. When serial console support is disabled in coreboot, the coreboot table does not contain serial information. In this case U-Boot falls back to parsing the DBG2 table. Some AMD platforms or any other platforms that uses memory-mapped I/O advertise the debug UART using DBG2 subtype 0x0012 ("16550-compatible with parameters defined in Generic Address Structure"). U-Boot currently accepts only subtype 0x0000, causing DBG2 UART detection to fail and leaving no console output. Accept subtype 0x0012 as well and keep the existing handling logic. Signed-off-by: Desapogu Jayaramudu Reviewed-by: Simon Glass

serial: avoid redundant early UART initialization

2026-07-28T18:30:55Z

When DEBUG_UART and SKIP_EARLY_DM are enabled, the serial console is still probed before relocation even though DEBUG_UART already configures the UART and provides early console output. The debug UART configuration is sufficient until relocation, making full serial driver initialization at this stage unnecessary. Furthermore, the initialization is slow since it runs with dcache disabled and is repeated again after relocation. Skip pre-relocation serial probing in this configuration and defer full UART initialization until after relocation. Update the GENI UART probe logic accordingly. This removes redundant UART initialization and improves boot performance. Signed-off-by: Aswin Murugan

serial: sifive: remove busy-loops from getc and putc ops

2026-07-27T04:04:42Z

The DM serial framework in __serial_getc() and __serial_putc() already retries when driver ops return -EAGAIN, calling schedule() between attempts to service the watchdog. sifive_serial_getc() and sifive_serial_putc() spin internally on -EAGAIN, which prevents the framework from calling schedule(). This can lead to watchdog timeouts when waiting for RX data or TX FIFO space. Remove the busy-loops and return -EAGAIN directly from the underlying helpers, letting the framework handle retries with proper watchdog servicing. This is consistent with how other DM serial drivers (pl01x, meson, cortina, etc.) implement their ops. Signed-off-by: Naveen Kumar Chaudhary Reviewed-by: Leo Yu-Chi Liang

serial: esp32: add driver for esp32 series chips

2026-07-23T21:16:22Z

Add a driver model serial driver for Espressif ESP32 UART controllers. The driver supports ESP32, ESP32-S3 and ESP32-S31 UART register variants, including baud-rate setup, FIFO access and basic port initialization. Signed-off-by: Honbo He Changes in v3: - Add debug UART for early print output

serial: lpuart: Clear the OR STAT in tstc to prevent hang

2026-07-12T08:18:32Z

Clear the STAT register OR bit every time in .tstc callback, otherwise a condition may occur when data are fed into the RX FIFO, the FIFO did overflow, the OR bit is set and prevents any new data from being added into the RX FIFO, the OR bit is never cleared, and watermark read back is always 0. If this condition occurs, the .tstc callback will always report no new characters, and the OR bit will never be cleared, so the U-Boot shell will be unresponsive until next reboot or kernel boot. This is easy to trigger on MX95, power on the system and send traffic on UART from host to the MX95, the MX95 FIFO will overflow and the U-Boot console will become unresponsive. Fix this by clearing the OR bit early, in .tstc callback. This way, even if an overflow occurs, there will be slight loss of RX data, but the U-Boot console will not become unresponsive. Signed-off-by: Marek Vasut Signed-off-by: Peng Fan

serial: lpuart: Use livetree API for fdt access

2026-06-26T20:06:39Z

Use livetree API, otherwise driver will fail to read properties from the device tree when OF_LIVE is enabled. Signed-off-by: Peng Fan

Kconfig: drivers: restyle remaining

2026-06-25T21:00:58Z

Restyle all Kconfigs for the rest of "drivers": Menu entries : no space left Menu attributes: 1 TAB Help text : 1 TAB + 2 spaces Replace '---help---' by 'help' Signed-off-by: Johan Jonker [trini: Add missing indentation on a few more multi-paragraph help texts] Signed-off-by: Tom Rini

serial: goldfish: return error when device address is invalid

2026-06-23T18:37:21Z

goldfish_serial_of_to_plat() returns success even when dev_read_addr() fails to find a valid address. This leaves plat->reg unset and defers the failure to probe(). Return -EINVAL immediately when the address is FDT_ADDR_T_NONE so the failure is reported at the of_to_plat stage where it belongs. Signed-off-by: Naveen Kumar Chaudhary Acked-by: Kuan-Wei Chiu

serial: cortina: check RX FIFO status before reading data

2026-06-23T18:37:02Z

ca_serial_getc() reads from the URX_DATA register unconditionally without first checking whether the RX FIFO contains valid data. When the FIFO is empty, this returns whatever stale value is in the register, which the DM serial framework interprets as a valid character. The DM serial framework expects getc() to return -EAGAIN when no data is available, so it can handle retries and call schedule() to service the watchdog between attempts. Add a check of the UINFO register's UINFO_RX_FIFO_EMPTY bit before reading URX_DATA, returning -EAGAIN when no data is pending. This is consistent with how ca_serial_putc() already checks UINFO_TX_FIFO_FULL before writing. Signed-off-by: Naveen Kumar Chaudhary